I think both teams accept

So.. why would Leafs trade Kerfoot for a 4th liner?

I doubt the panthers would accept that tbh

Might have to add kerfoot in the panthers trade instead of the preds one

Why would Nashville go after someone who isn't a top 6 scoring winger? Trade doesn't make sense for either team.

They are getting mid-6 center. Which would allow them to use a guy like Duchene on wing where he is more effective as a speedy threat. Or Kerfoot as 3C which adds significant depth.

Forsberg - Johansen - Arvidsson
Tolvanen - Duchene - Jarnkrok
Trenin - Kerfoot - Tomasino
Cousins - Sissons - Grimaldi

Or

Forsberg - Johansen - Arvidsson
Duchene - Kerfoot - Tomasino
Tolvanen - Sissons - Jarnkrok
Trenin - Cousins - Grimaldi

I get why they would want Kerfoot but not for only Cousins.. if it was Jarnkrok, maybe..

You're missing Kunin in those hypothetical Preds lines.

Kerfoot is a 3rd line center, not a 2nd line player. NSH has tons of bottom six center depth and wouldn't have any interest in Kerfoot. Cousins was brought in specifically because of his value as a pest and sh*t disturber, which is an element NSH was lacking. Kerfoot doesn't provide that.